Furnace sealing device and gas control



April 2, 1935. o. J. BLANCHET 1,996,554

FURNACE SEALING DEVICE AND GAS CONTROL Filed Jan. 5, 1934 2 Sheets-Sheet 1 dy WITNESS. 62 V April 1935- o. J. BLANCHET 1,996,564

FURNACE SEALING DEVICE AND GAS CONTROL Filed Jari. 5, 1934 2 Sheets-Sheet 2 OV/AA J 544M072? J) Patented A r. 2, i935 um'rso STATES PATENT OFFICE 1 FURNACE SEALING DEVICE AND GAS CONTROL Ovila J. Blanchet, New Bedford, ram. Application January s. 1034, Serial No. 705.321

14 Claims. (Cl. ass-z) This invention broadly relates to improvements in electric furnaces for heat treating purposes, and more particularly, thesame has reference to anelectric annealing furnace sealing means and a gas control mechanism therefor.

In the art of heat treating the shanks of drills or the like, it is the practice to insert the shanks into either an electric furnace operable either on the inductance or resistance principle, and the same heated in the presence of a non-oxidizing atmosphere to avoid discoloration of the tool. To accomplish this result, a gas is admitted to the respective heating chambers, and it is therefore the purpose of this invention to seal the furnace openings when the tools are inserted therein to exclude the entrance of air from the heating chambers and to prevent the escape of the gas and heat from the heating chambers, and to automatically open the feed of the gas to the heating chambers when the tools are inserted therein, and for shutting off the flow of gas to the chambers when the drills have cooled and are withdrawn.

Another object of the invention resides in an electric switch means operable upon engagement of the drill holder with the electric furnace when a drill or gang of drills are inserted into the furnace for heat treating, for closing an electric circuit to open the gas valve to admit gas to the drill heating chambers, the circuit being broken upon the withdrawal of the drill holder to cause automatic closing of the gas valve.

Another feature of the invention is the provision of a sealing gasket for drill heating purposes having an opening normally greater than the diameter of the drill to be heat treated, and means for contracting the walls of the opening about the drill upon insertion of the same, through the opening whereby to provide a tight seal between the gasket and the drill.

with these and other objects in view, the invention resides in the certain novel construction, combination and arrangement of parts, the essential features of which are hereinafter fully described, are particularly pointed out in the appended claims, and are illustrated in the accompanying drawings, in which:

Figure l is a diagrammatic illustration of my invention showing part in side elevation and part in section.

Figure 2 is a front elevational view of an electric drill heating furnace showing my improved sealing gasket in position thereon.

Figure 3 is an enlarged vertical transverse sectional view through an electric drill heating furnace with the sealing gasket and circuit control switch in operative position.

Figure 4 is a fragmentary top plan view with parts broken away in section. v

Figure 5 is a front elevational view of the drill holder gasket.

Figure 6 is a rear elevation of the drill holder gasket.

Figure 7 is a rear elevational view of the furnace sealing gasket.

Figure 8 is a front elevational view of the furnace sealing gasket.

Figure 9 is a perspective view of the furnace sealing gasket member showing the two cooperating gasket sections in separated position, one of the sections having the gasket linings removed.

Figure 10 is an enlarged vertical sectional view through the gas control valve.

In the art of annealing drill shanks and other analogous articles, it is necessary to trap a nonoxidizing atmosphere in an annealing chamber and to insert and remove the drills to be annealed in such a way as to-cause a minimum release of or interference with the atmosphere to avoid discoloration of the drills, which, from a commercial standpoint is objectionable. The invention which will now be described aims to avoid the discoloration of these drills during an annealing process by sealing the drill receiving openings in the furnace and operates to control the flow of annealing gas to the annealing chambers in timed relation with the insertion and withdrawal of the drills relative to the said chambers.

Referring to the drawings by reference characters, the numeral ill designates a conventional type of electric drill annealing furnace including a casing l I having a plurality of spaced horizontally alined heat treating or annealing chambers l2, suitably insulated from the casing and from each other by insulating material IS. The front wall of the casing is provided with drill receiving openings II which communicate with the respective chambers l2, and which openings are of a diameter greater than the diameter of the drill shank to be annealed to facilitate the free insertion of the same into the chambers. Each chamber I2 contains a heating coil ii, the convolutions of which are greater than the diameter of the drills to be annealed and the same are disposed in axial alinement with the openings I4 and in spaced relation to the walls of the chambers. The heating coils of the respective chambers are connected together in series and the same arranged in an electric heating circuit, not shown.

Entering each chamber I! through the rear thereof is a gas inlet pipe |4 connected to a gas supply pipe I! which leads to a gas supply tank I! containing nitrogen or other gaseous fluid used in the formation of a non-oxidizing atmosphere within the heat treating chamber. Arranged within the pipe line II for controlling the flow of gas therethrough is a control valve Is the construction and operation of which will be hereinafter explained.

Fixed to ,the exterior of the furnace casing H at the front thereof in axial alinement with each opening I4 is a furnace opening sealing gasket device 20. The sea gasket device 20 includes a shell 2| of a di-electric material and comprises a front wall 22 and a continuous flange 23 disposed at right angle to the front wall. Ears 24 formed integral with the shell 2| extend fromopposite ends thereof through which screws or like fastening elements 25 pass for securing the device 20 in position upon the front of the furnace. The front wall 22 centrally thereof is provided with a relatively large opening 26 for the free passage of the drill to be annealed, while disposed at equal distance from the opening 26 on opposite sides thereof are two smaller size openings 21, the purpose of which will be explained hereinafter.

Fitting within the shell 2| for expansion and contractive movement therein are a pair of separate coacting metallic gasket members 28-28. Each gasket member 28 has a substantially semicircular shaped body portion 29 terminating in outwardly extending hook shaped ends 30, the inner curved surfaces of the ends 30 constituting seats 3| while the extreme flat surfaces 32 act as abutting stops for limiting the expansive movement of the members in their assembled position. The inner concave wall of the body portion 29 is provided with a groove or channel 33 to receive and hold the rib 34 of a yieldable asbestos sealing lining 35. One side face of the body 29 of each member 28 is notched adjacent the hooked ends 30 as at 36, the depth of the notch being approximately one-half the thickness of the body whereby the hooked ends may be crossed with the members in reverse positions as shown in Figure 7. The notches 36 are of a shape and size to permit contractive movement of the members 28 when in the normal expanded position shown in Figure 7 wherein the flat ends 32 thereof are in abutting engagement. The interior of the shell 20 is of a size and shape to snugly receive the coacting gasket members 28 with the outer sides of the body portions 29 of the said members abutting the flange 23 of shell when expanded, while the hook portions 30 are at all times in spaced relation to the adjacent portions of the flanges. Engaging the outer curved surfaces of the hook portions 36 of the two gasket members are arcuate shoes 31 and interposed between the shoes and the adjacent spaced portions of the flange 23 are springs 38, which act to expand the body portions of the members 28 and contract the hook portions thereof so that the coacting curved seats 3| form restricted passages in alinement with the respective openings 2'! in the shell 20 as best seen in Figure 8. The shoe 3! of one of the sealing gasket devices has a threaded terminal post 39 connected thereto and which extends outwardly through the shell and threadedly receives a clamping nut 48'. In Figure 2 of the drawings, the terminal connector is provided on the left end gasket sealing device, for in a gang furnace it is only necessary that one of the sealing devices be so equipped.

For the purpose of holding one or a gang of drills to be annealed I provide a drill holder block 40 of di-electric and of a low heat absorbing material, the same being provided with a series of sockets 4| equal in number to the number of heat chambers of the furnace l6 and axially spaced relative to the furnace whereby the holder may be brought to an operative position with the sockets 4| in alinement with the respective openings 26 and I4. The drill holder 40 is also provided with sealing gasket devices 42 attached to that face onto which the sockets 4| open, and which devices are positioned about the respective openings. Adescription of one of such sealing devices 42 will suflice for the others and the same will now be described.

Each sealing device 42 comprises a metallic shell or casing 43 somewhat similar in shape to the shell or casing 2| and having a rear wall 44 and a continuous right angularly disposed flange 45. The rear wall 44 is provided with a central opening 46 similar in size to that of the opening 26, while extending from opposite ends of the casing are cars 41 having openings therein through which fastening elements 48 pass and enter the holder block 46. One of the cars" is extended and supports a terminal post 48 to which a clamping nut 50 is threaded. Nested within the shell or casing 43 is a flller 6| of di-electric material and secured in position therein by two contact studs 52, each stud having an enlarged conical head 53 and a reduced shank 54 fixed to rear wall 44 of the metallic shell 43. The studs are respectively disposed on opposite sides of a central opening 55 which is slightly larger in diameter than the opening 46 but in axial alinement therewith. The wall of the opening 55 is provided with a groove 56 in which the rib 51 of an asbestos or other yieldable heat insulating gasket 56 is seated and held. The studs 52 are so spaced that they axially aline with the openings 21 when the holder sealing device 42 is brought into operative engagement with the coacting furnace sealing device 20 in a manner and for the purpose hereinafter explained.

The control valve |9 hereinbefore mentioned comprises a casing 59 having a cylindrical bore 69 opening to the atmosphere at the top end through openings 6| and by an opening 62 at the bottom. Arranged within the casing for sliding movement in the bore 66 is a valve head 63 having a transverse passage 64 adapted to be moved into alinement with the pipe line I! which enters the casing 59 to open the line, and to be moved out of alinement therewith to shut oif the supply through the pipe line. A valve actuating rod 64' has one of its ends flxed to the valve head 63 and while its opposite end is provided with an enlarged iron core 65 forming part of an electric solenoid 66. An arm 61 extends from the core 65 and has pivotal connection with one end of a rocker arm 68, pivoted intermediate its ends upon the top of a standard 69, the other end of the rocker arm having a counter balance weight 10 supported therefrom. The weight 10 serves to normally hold the core 65 and valve head 63 in a raised position, and with the passage 64 out of registration with the pipe line H, or in closed position. The solenoid 66 is arranged in an electric circuit with a source of electrical energy, one end of the solenoid winding being connected by a wire TI to the terminal 49 of one of the holder sealing devices 42 while the other end of the solenoid winding is connected by a wire 12 leading to the source of electrical energy. A wire 13 also leadingtothesourceofeiectrical energyisconnectedtotheterminalpostfl. Itwilltherefore 'beseenthattheholdingsealingdeviceflcoactswithamatingfurnacesealingdevice "to provide an electrical switch for closing the solenoid unit to energize the solenoid l0 and draw the core 0! inwardly to move the valve head .8 to open position, the opening movement of the valve head being limited by contacting engagement with a stop flange 14 within the casing II.

In operation of the invmtion. assume that it is desired to anneal the shanks of a "gang" of drills of a particular diameter. The cutting end ofeachdrillaisinsertedintoasocketll ofthe holder block II, the said end ilrst paming through the gasket ll of the holder sealing device 42. The diameter of the gasket II is slightly smaller than the diameter of the drill so that upon insertion, the gasket will yield upon insertion of the drill and snugly embrace the drill at its entrance to the socket. After arranging the drills in the respective sockets of the holder with the shank ends extending therefrom, the holder is brought into position adjacent .the furnace II as shown in Figure l, whereupon the extending drill shanks arealined with the openings in the furnace sealing devices 2., whereby the shank ends may be inserted into the respective heat annealing chambers, it being understood that the sealing gasket sections Il2i are in a normally expanded position to facilitate the free insertion of the drill shanks therethrough. As the drill shanks near the end of this movement to a full inserted position, the conical heads I of the contact studs 52 pass through the openings 21 in the casing II and engage the seats ii of the hooked ends of the members 28, the said seats normally coacting to provide a restricted passage for the contact studs. The beveled surfaces of the conicalheads engage the seats and continued inward pressure thereon causes the hooked ends to be wedged apart, which action causes the body portions 28 of the members 20 to be drawn toward each other, whereupon the gaskets 35 are contracted about the drill shanks to tightly seal the interior of the annealing chambers from the atmosphere to prevent entrance of atmospheric air therein and to avoid loss of the non-oxidizing gas therefrom.

From the description thus far, it will be understood that the sealing devices 20 have all been contracted about the drill shanks and the furnace I0 is now ready for operation. The current to the heating coils I! may be turned on to heat the annealing chambers. During the positioning of the drill shanks in the respective annealing chambers and the sealing of the chamber openings by the sealing devices 20, one of the studs 52 of the sealing device 42 containing the terminal post 49 has entered that sealing device 20 on which the terminal post 39 is mounted. Thus one set of mating sealing devices 20 and 42 when brought together act as a switch for closing the solenoid circuit, which causes the solenoid core I to be drawn inwardly of the solenoid and in turn actuate the rod to move the valve head 83 to open position against the action of the counter-balance weight ll. Opening of the valve ll permits gas to flow from the tank ll to the respective annealing chambers l2 and set up therein a non-oxidizing atmosphere about the drill shanks during the heat treating or annealing process. After the drill shanks have been subjected to the required heating, the same are left to cool and if desired, the supply ofgastothechamber limaybemanuallyshut oifbytheactuationofahandvalvellonthe tank ll. Afterthedrillshankshavebeensufiiciently cooled and assuming that the valve "II is open, the operator draws the holder ll away from the furnace II and withdraws the drill shanh therefrom. Just as soon as the heads of the studs If clear the seats I, the springs II expand the members 2|, thus releasing the same fromaboutthedrillshanksandreturning the members to their normal position. As the' electric contact stud of one of the sealing devices 42 is cleared from its engaging contact, the solenoid circuit is of course broken, which deenerglzes the solenoid and allows the balance weight I. to return the valve head I to its normal closed position.

While I have shown and described what I deem to be the preferred embodiment of my invention, I wish it to be understood that such changes and modifications maybe resorted to as come within the scope of the appended claims.

Having thus described the invention, what I claim as new and desire to secure by Letters Patent of the United States, is:--

1. In a furnace for the treatment of an anticle or articles in the presence of heat and gases, a controlled gas supply for admitting gas to said furnace, means for sealing said furnace upon the insertion of an article therein to be treated. and means simultaneously operable by the insertion of the article in said furnace for admitting gas thereto.

2. In a furnace for the treatment of an article in the presence of heat and gases having an opening to the atmosphere, a controlled gas supply for admitting gas to said furnace, means for sealing said opening to the atmosphere upon the insertion of an article therethrough to be so treated, and means operable by the insertion of the article into said opening for admitting gas to said furnace.

3. In a furnace for the treatment of an article in the presence of heat and gases having an opening to the atmosphere, an electrically controlled gas supply for admitting gas to said furnace, means for sealing said opening to the atmosphere upon the insertion of an article therethrough to be so treated, and electric means operable by the insertion of the article into said opening for admitting gas to said furnace.

4. In a furnace for the treatment of an article in the presence of heat and gas having an opening to the atmosphere, a controlled gas supply for admitting gas to said furnace, an article holder for supporting the article to be inserted through said opening to be treated, and means operable by said article holder upon insertion of the article through said opening and into said furnace for admitting gas to said furnace.

5. In a furnace for the treatment of an article in the presence of heat and gas, an electrically controlled gas supply for admitting gas to said furnace, an article holder for supporting the article to be inserted through said opening to be treated, and electric switch means operable by the presence of said article holder adjacent said furnace for operating said electrically operated gas supply for admitting gas to said furnace.

6. In a furnace for the treatment of an article in the presence of a confined atmosphere having an opening to the atmosphere, a normally expanded adjustable sealing device mounted on said furnace about said opening, and means operable for contracting said sealing denace about said opening,

vice about the article after insertion of the same through said opening. 7. In a furnace for the treatment of an article in the presence of a confined atmosphere having an article receiving opening, a normally adjustable sealing device mounted on said furan article holder adapted to support the article to be inserted through said opening and into said furnace, and cooperating means on said holder and said sealing device for contracting said sealing device upon the positioning of said holder adjacent said furnace to insert an article therein.

8. In a furnace for the-treatment of an article in the presence of heat and gas having an article receiving opening, a sealing device mounted on said furnace about said opening, said sealing device including a pair of separated resilient normally expanded gasket members, an article holder for supporting an article to be inserted through said opening into said furnace, and cooperating means between said holder and said gasket members for contracting said gasket members about an article inserted into said furnace and held by said holder.

9. In a furnace for the treatment of an article in a confined atmosphere having an article receiving opening larger in size than the article to be inserted therethrough, a gasket sealing device mounted on said furnace about said opening, said sealing device including a pair of separable semi-circular shape complementary gasket members coacting toprovide a sealing gasket, the ends of said gasket members terminating in oppositely turned hook portions, the ends of the gasket members being crossed to cause the same to coact and provide a pair of restricted open; ings, spring means acting upon said gasket members to normally expand the same and to cause the ends of the hook portions to abut, an article holder, a sealing gasket device mounted on said article holder, said last mentioned sealing device including a pair of spaced beveled studs of a size greater than the normal size of the openings formed by the hooked ends of the gasket members for wedging engagement with the walls of the said last openings to spread the hooked ends apart and simultaneously contract the gasket members about an article supported by said holder when inserted through the first mentioned sealing device and into said furnace.

10. In a furnace opening sealing device of the class described, a furnace opening sealing gasket including a pair of separate normally expanded resilient gasket members, a holder sealing gasket adapted to be brought into engagement with said furnace sealing gasket, and cooperating means between said gasket members and said holder sealing gasket operable upon bringing thetwo sealing gaskets together for contracting said gasket members.

11. In a furnace opening sealing device of the class described, a furnace opening sealing gasket including a pair of separate normally expanded resilient gasket members, a holder sealing gasket adapted to be brought into engagement with said furnace sealing gasket, and cooperating means between saidgasket members and said holder sealing gasket operable upon bringing the two sealing gaskets together for contracting said gasket members, said cooperating means comprising crossed hooked ends on said gasket members to provide normally restricted openings, and conical studs on said holder sealing gasket for reception in said restricted openings for wedging engagement with the walls thereof to expand said hooked ends and simultaneously contract said gasket members.

12. A sealing gasket device comprising a shell having an opening therein, attaching means on said shell, a filler nested within said shell having an opening therein in axial alinement with said first mentioned opening but of the same or less diameter, and a yieldable gasket secured to the walls of said last mentioned opening and projecting inwardly thereof.

13. In a furnace for the treatment of an article in the presence of heat and gases having an opening to the atmosphere, a controlled gas supply for admitting gas to said furnace upon the insertion of an article therein to be treated, and means operable by the insertion of the article through said opening for admitting gas to said furnace.

14. In a furnace for the treatment of an article in the presence of heat and gases having an opening therein to the atmosphere through which an article to be treated is adapted to be inserted, expandable and contractible sealing means for sealing said opening after the insertion of an article therethrough, a gas supply for said furnace, a normally closed electromagnetically operable control valve for said gas supply, a normally open electric circuit in which said electromagnetic valve is arranged, and electric switch means in said electric circuit operable when the sealing means is in contracted position for closing said electric circuit to actuate said electromagnetic valve to on position to admit gas to said furnace.

OVILA J. BLANCHET. 

